loading
I am currently looking for someone to help out with this blog. I didn't realize the scope that this blog would effect. Hits from countries in political strife and the like, people looking for a way to communicate outside of government control. If you would like to help please send me an email George dot Endrulat at Gmail dot Com.

Wednesday, May 25, 2011

Mesh network basics

Mesh network basics
02-06-2011, 11:55 PM
Senior Member
Join Date: Mar 2008
Posts: 729
Default Mesh network basics

Mesh Networks:

A mesh network is a team of APs that interact with each other on their radio side. All APs are on the same channel. All APs are aware of the Radio Frequency ( RF ) and network performance parameters of other meshed APs within radio range. All APs report information on their neighbors; received signal strength, network throughput and other parameters.

Mesh networks are Ad Hoc networks. There is no central AP that all others must associate with. Every AP in a mesh network is also a client of its neighbors. Each AP reports the number of clients it has associated with. The mesh creates a self-healing network that routes network traffic based on the workload of the APs in use and the RF performance of the meshed APs. Only one AP needs to be connected to a wired LAN to give the mesh clients access to that LAN.

You can create an inexpensive mesh network with Linksys WRT54G routers and freifunk firmware. Freifunk network APs can be configured on the CAT5 side, but not through the wireless interface. You can plug a different ISP into any router. The clients will connect to the internet through the nearest router with Internet access. If any ISP fails, the clients will connect to the nearest working ISP when they refresh their browsers. Free. Easy to configure.

Freifunk networks are open and unsecured. If you need access control, you need to configure that by inserting a server between the ISP and a mesh router, or by using VPN on all auhorized clients

The range of the mesh network is the combined area of all the APs. Some overlap is necessary to form a mesh, but the combined coverage of a dozen APs is much larger than the coverage of one AP.

Enterprise grade mesh networks use two radios per node. One radio uses 5.8 gHz for the mesh, the other provides 2.4 gHz access to the end users. This reduces overhead anddata packet collisions.

Mesh network, step by step:

Mesh networks are best explained graphically:

















A large drawing of a Freifunk network in Leipzig
http://db.leipzig.freifunk.net/uptime/png/

Things to remember:
  • A typical one AP wireless network has one point of failure; the AP
  • A failure of one AP is not a problem in a mesh network
  • A mesh network can cover a much larger area than one AP
  • Mesh networks are self generating and self healing

Links:

English Wiki

Freifunk Firmware (English)

freifunk-texas.net How To page with an outdated firmware link ( use the link below for newest firmware )

the latest firmware at the time this was written:

Index of /ipkg

B.A.T.M.A.N.

kw: mesh, networking, freedom, p2p, internet, bitcoin, asterisk, google, google voice, android, root, free, wireless, data, linux, voip, voice

No comments:

Post a Comment